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B1 Cell level systems

6 dot points across 6 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

How are eukaryotic and prokaryotic cells built, and how does each sub-cellular structure carry out its job?

Eukaryotic and prokaryotic cells, the function of sub-cellular structures (nucleus, chromosomes, cytoplasm, cell membrane, mitochondria, ribosomes, chloroplasts, permanent vacuole, cell wall, plasmids, flagella), and how the structure of each is related to its function.
A focused answer to the OCR Gateway GCSE Biology A topic B1 on cell structures, covering eukaryotic and prokaryotic cells, the function of every sub-cellular structure, and how structure is related to function in animal, plant and bacterial cells.
9 min answer →

How does the sequence of bases in DNA carry the code to build a protein?

The structure of DNA as a double helix of two strands made of nucleotides, complementary base pairing (A-T, C-G), the gene as a section of DNA coding for a sequence of amino acids, and an overview of protein synthesis using mRNA and ribosomes.
A focused answer to the OCR Gateway GCSE Biology A topic B1 on DNA and protein synthesis, covering the double helix, nucleotides, complementary base pairing, the gene as a code for a protein, and the overview of transcription and translation using mRNA and ribosomes.
9 min answer →

How do enzymes speed up reactions in cells, and why do temperature and pH change how fast they work?

Enzymes as biological catalysts, the lock and key model and active site specificity, the effect of temperature, pH and substrate concentration on the rate of enzyme-controlled reactions, and denaturing of enzymes.
A focused answer to the OCR Gateway GCSE Biology A topic B1 on enzymes, covering enzymes as biological catalysts, the lock and key model and active site specificity, the effects of temperature, pH and substrate concentration, denaturing, and the rate of reaction practical.
10 min answer →

How do microscopes let us see cells, and how do we calculate their real sizes from a magnified image?

The use of light and electron microscopy to study cells, the difference between magnification and resolution, the magnification equation, rearranging it to find real size or image size, and using standard form and SI units (mm, micrometre, nm) for cell sizes.
A focused answer to the OCR Gateway GCSE Biology A topic B1 on microscopy and magnification, covering light and electron microscopy, the difference between magnification and resolution, the magnification equation, unit conversions, and using standard form for cell sizes.
9 min answer →

How do plants make glucose from light, and what slows photosynthesis down?

Photosynthesis as an endothermic reaction in chloroplasts, the word and symbol equations, the uses of glucose made by the plant, limiting factors (light intensity, carbon dioxide concentration, temperature), and the inverse square relationship between light intensity and distance.
A focused answer to the OCR Gateway GCSE Biology A topic B1 on photosynthesis, covering the endothermic reaction in chloroplasts, the equations, the uses of glucose, the limiting factors, the inverse square law for light intensity, and the photosynthesis practical.
10 min answer →

How do cells release the energy they need from glucose, with and without oxygen?

Respiration as an exothermic series of reactions that releases energy from glucose in all living cells, the word and symbol equations for aerobic respiration, anaerobic respiration in animals (lactic acid) and yeast (ethanol and carbon dioxide), oxygen debt, and the uses of the energy released.
A focused answer to the OCR Gateway GCSE Biology A topic B1 on respiration, covering aerobic respiration and its equations, anaerobic respiration in animals and yeast, oxygen debt, and the uses of the energy released in cells.
9 min answer →